I was wondering if it was possible to motion tween an flv while it's playing?
So far I can mask the flv with an animated object, animate objects behind the video, and in front. I tried animating the video itself and as soon as the movie plays in preview the animation stops.
animate it with actionscript.
It sounds like you're trying to animate the FLVPlayback playing an FLV?
It's true of all components in Flash that they'll animate on the Stage, but not at runtime. The way to get them to animate at runtime is to wrap them in a movie clip first. As soon as you do this, you'll see the animation.
(if you're using new motion, you can copy your existing tween as a motion preset and reuse it).